Benign prostatic hyperplasia: A common, noncancerous enlargement of the prostate gland. The enlarged prostate may compress the urinary tube (urethra), which courses through the center of the prostate, impeding the flow of urine from the bladder through the urethra to the outside. Abbreviated BPH. If BPH is severe enough, complete blockage can occur. BPH generally begins after age 30, evolves slowly, and causes symptoms only after age 50. Half of men over age 50 develop symptoms of BPH, but only a minority need medical or surgical intervention. Medical therapy includes drugs such as finasteride and terazosin. Prostate surgery has traditionally been seen as offering the most benefits'and the most risks'for BPH. BPH is not a sign of prostate cancer. Also known as benign prostatic hypertrophy and nodular hyperplasia of the prostate.